It's unlikely Preact infringes on a theoretical React patent. It's not a reverse-engineered reimplementation of React, but rather a library that happens to have a similar public API. APIs are not patentable, thus Preact's implementation is no more likely to infringe than Angular or Vue's.
Also impossible because JSX is independent of React. The specification is only subject to a standard Copyright and is released under the Creative Commons Attribution 4.0 International license.
I'd be curious to hear about this too - I don't see any issues filed or commented on by him, perhaps the bugs are more perceptual mismatches with his React experience as opposed to actual bugs. We only recently released preact/debug, which brings with it some of the guardrails React ships by default - maybe without those people run into issues.
FWIW there are hundreds of companies (some very very large) using Preact in production. If there were showstopper bugs, they'd be fixed immediately.
I think this may be referring to "preact-compat" issues rather than Preact issues. I know the Inferno team recently had to change a lot of the state scheduling to be 1:1 with React 15/16 (i.e. batch sync schedule setState after events was very broken and there were issues with controlled components in Safari).
> Its internals are fundamentally different and not a derivative work.
That would be a strong defence to a copyright claim. We're talking about patents, where there is no concept of "derivative works", and what matters isn't implementations but broad concepts.
> Software interfaces cannot be patented
Right, but what makes Preact concerning isn't that it offers the same API, but that it is built using the same underlying concepts.
Preact renders independent, encapsulated, nested, functional-ish components, usually but not always written in JSX, into a virtual DOM. Components are rerendered to the virtual DOM when their inputs change, and then diffing is used to efficiently sync the virtual DOM with the browser DOM.
If Facebook has some sort of patent covering the virtual DOM (although thankfully as far as I know, they don't), it's hard to see how it would not also cover Preact. And this is true even if, as I assume is the case, Preact shares 0 lines of code with React.
Edit: To be clear, I don't believe the patent situation is concerning, I think Preact is a great project, and I may well be using it in production soon. But if I was worried about Facebook's patent portfolio, I would be worried about using Preact.
Understandable, and agreed about my point being for copyright as opposed to patents. It's interesting to note that, since the majority of DOM rendering libraries now employ some variant of Virtual DOM (react, preact, mithril, glimmer/ember, angular, even polymer!), a patent claim covering the concept of Virtual DOM itself would likely be invalid - the presence of so many prior and contemporary implementations of that paradigm make would invalidate it on the grounds that it cannot be "Non-obvious" or "non-novel". My knowledge of this stuff is largely gleaned from Wikipedia and thus not to be trusted, but it seems like there would be little grounds for a patent suit over VDOM. Also interesting to note: there are few (if any?) other companies directly associated with any of the other VDOM implementations - can a patent claim even be made against an Open Source project?
Yup, though the Rax benchmarks are especially bad. Calling a function with unchanging arguments in a loop with a constant number of iterations is going to trigger about the least real-world performance characteristics you could ask for, haha. I'm happy to see more people getting into the VDOM space, but it sucks to have to explain all the pitfalls every time a new broken benchmark comes out.
